1. Field of the Invention
The invention relates to a method for producing a battery.
2. Description of the Related Art
At the battery production processes, there is an art in which an electrode assembly is wound and then flattened by pressing, and there are documents that disclose the same (refer, for example, to Japanese Patent Application Publication No. 2010-198987 (P2010-198987 A)). In addition, there is a document that discloses an art in which, when an electrode assembly is wound, a rod-shaped spacer is inserted in parallel to the direction of the shaft center for the wound electrode assembly in order to form a space in the electrode assembly after winding (refer, for example, to Japanese Patent Application Publication No. 2003-157888 (JP2003-157888 A)).
In the ease of an electrode assembly formed as in JP2010-198987 A, the stress produced in the electrode assembly during pressing may concentrate in one region and creasing and strain may be produced in the electrode assembly as a result. When this creasing and strain remain present, the shape of the battery may occur deformation and the reduction of the battery quality, e.g., the volumetric energy density and cycle characteristics, by the expansion and contraction of the electrode assembly during charge/discharge.
On the other hand, in the case of the art according to JP2003-157888 A in which a spacer is inserted in the electrode assembly in order to form a space in the electrode assembly after winding, it has not been possible to effectively prevent the production of creasing and strain in the electrode assembly during pressing because pressing is carried out with the spacer inserted in the electrode assembly.